Improvement in machines for threading bolts



T. THOMAS. Machine for Threading Bolts.

Nb. 207,084. Pate'nt ed Au 13, I878.

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UNITED STATES PATENT OFFICE.

THOMAS THOMAS, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN MACHINES FOR THREADING BOLTS.

Specification forming part of Letters Patent No. 207,084, dated August13, 1878; application filed June 11, 1878.

To all whom it may concern:

Be it known that I, THOMAS THOMAS, of Pittsburg, in the county ofAllegheny and State of Pennsylvania, have invented a certain new anduseful Improvement in Bolt- 'Threading Chucks; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itpertains to make and use it, reference being had to the accompanyingdrawings, which form part of this specification, in which- Figure 1 is aside elevation; Fig. 2, a plan; Fig. 3, an end view; and Fi g. 4 alongitudinal middle section of Fig. 2.

The invention relates to bolt threading chucks for machines of thatclass in which the dies are held in vibrating jaws, which are caused toopen when the bolt has advanced to a predetermined point.

It consists in the hereinafter described and claimed means of opening,closing, and lock ing the vibrating jaws, and the combination thereofwith the chuck and its parts.

Except in some particulars the general form is of the usualconstruction, consisting of a hollow spindle, A, carrying at its outerend the box B, provided with the rabbeted or dovetailed slideway-head O,on which are arranged the two jaws D, grooved to slide on head (l, asshown, and having on their faces the die-holding cavities a a a a.

Passing through the hollow spindle A is a hollow tube, 1), to which,beyond the spindle, 1s screwed the collar 0, which is partly split andprovided with the clamping-screw d. A long rod, 6, passes through;collar 0 and pipe or tube 1), and is clamped to any position therein bycollar 0 and the screw d, so that if the rod e is pushed either way itcarries the tube 7) with it.

Tube 1) passes into the box B through a rubber or other cushion, f, andbeyond that screws into a cross-head, g, to each end of which aresecured the parallel bars h h, which pass forwardthrough the head (3,and have their outer ends inwardly inclined to form wedge-faces, asshown in Fig. 4. The adjacent faces of the vibrating jaws D have slotsor recesses 73, as shown.

Attached to the box B are springs s, hav-. ing slotted ends, throughwhich pass the studs k. These springs normally tend to separate the jawsD when free to act.

A block, E, is set or cast in the box B, be tween the bars h, to guidethem, and is perforated centrally for the passage of the bolt, as arealso the head 0 and jaws D. The wedge-faces on bars h and the slots tinjaws D are so proportioned relatively that the bars enter the slots to agreater distance than the length of wedge-face requires. The jaws D havehardened and removable wearing-faces m, which can be taken out andreplaced when required.

To operate, the device is fitted to the machine, after pushing forwardthe rod e, collar 0, and tube 1) as far as possible. the wedge-faces ofbars h to impinge on the inner edges of slots 2" and push the jaws Dinward. On advancing farther the bars h finally project into the slotsso far that their parallel sides bear upon the sides of the slots,- andin such position the jaws are locked firmly against the strain on thedies.

The bolt to be threaded enters the dies and is threaded as it advancestill its end strikes the end of rod 0 and pushes it ahead. This causestube 1) to recede also, drawing bars h out of the slots 6. Springs s actto separate the jaws D and dies, when the bolt is released and can bewithdrawn.

This construction enables me to previously adjust the rod to anyrequired length of thread, and, when once set, it will automati callyopen the dies at any required point.

The tube b may be made large, so as to take in different sizes of bolt.

I claim as my invention- The combination, with the box B, hollow spindleA, and spring-controlled jaws D, of the sliding tube b, rod e,'passingthrough said tube and adjustable in relation thereto, collar 0,clamp-screw d, cross-head g, and beveled parallel bars h h, with orwithout the block E, substantially as shown and'deseribed.

In testimony that I claim the foregoing I THOMAS THOMAS.

Witnesses THos. J. BRAY, T. J. MOTIGHE.

This causes

